# How Information Flows

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## Introduction

Computers are the most common means of gaining Internet access. There are many devices that may connect directly or indirectly to the Internet, such as pagers, cell phones, organizers, voice mail, memory sticks, and data watches. From a legal standpoint, you need to be aware of how each works at the digital level, the security concerns related to the use of a particular device, and how to properly preserve and legally obtain access to information of evidentiary value stored on each device that may be discovered during an investigation.

## Objectives

Upon completion of this topic, you will be able to recognize terms used to connect computers to the Internet and how information flows. To begin, select the forward arrow.

## IP Address

Every computer has a unique name and number. The name, like an office number, is assigned by the system or network administrator for ease of managing assets on the network. The number, called an Internet Protocol, or IP, address, is like a street address. A computer cannot connect to the Internet without an IP number. Unlike a piece of mail, which can be sent and delivered without a return address, communications cannot travel the Internet without IP addresses for both the sender and recipient. This is because the Internet works by means of various protocols, such as the Internet Protocol, which are standards agreed on by the developers of the Internet. Without these standards, different computers would not be able to understand each other.

## IP Address (contd.)

The IP address consists of four sets of numbers ranging from zero to 255 separated by periods, such as 123.45.67.101. These IP addresses are very important during computer crime investigations because they may be used to trace back to a suspect or witness. However, you should be aware that a perpetrator can use false IP addresses.

## Internet Service Provider

To get an IP address, a user must use an Internet Service Provider, or ISP. An ISP can be a provider of service to the public, like AOL or Juno, or can be a restricted site provider, like DoD or IBM. A service provider, as implied by the name, is an entity which provides users with the ability to send and receive electronic communications.

## IP Address Assignments

Because ISPs have more customers or users than they have IP addresses, they commonly put their assigned block of IP addresses into a pool. When a customer or user connects with the ISP, an IP address is assigned to the user's computer for the duration of the user’s session. The ISP generally keeps logs showing who used a particular IP address at a particular time and date. These records are the means used by investigators to trace back to suspects.

## IP Static or Dynamic?

An IP address can be static or dynamic. A static IP is always assigned to the same computer, while a dynamic IP is assigned to different computers as needed. When you are assigned an IP address after connecting to your ISP, your computer gets a dynamic IP address.

## Domain Names

IP addresses are appropriate for computers to use to communicate with each other, but have a lack of appeal for humans. Because it is difficult for humans to remember the string of numbers, IPs are translated into domain names such as amazon.com, army.mil, or defenselink.mil. Domain names can be generic, such as .com, .gov, .net, and .org; or country code, such as .ca for Canada, .uk for United Kingdom, and .de for Germany. Countries are often assigned blocks of sequential IP numbers, as well. Now that you have an ISP and an IP number, you are ready to send and receive information over the Internet. Let's look at how information moves across the Information Superhighway.

## Packets

For example, when you type an email and hit the send button, several things happen that you don’t see. Before any information travels in the digital world, it is converted into zeros and ones, or binary numbers. The information is then broken down into small bundles, or packets. Each packet must include a header with address information. A packet is like an envelope. The header is the address and the body of the message is the information being sent. This distinction between the header and the body of the message is important when you consider using pen register/trap and trace devices or wiretaps. The several packets making up the email pass through routers, which are like a post office and traffic center. The router will determine which pathway is the fastest for each packet. The packets travel separately to the destination. When the packets arrive at the destination computer, they are reassembled, translated from the binary numbers into the message you sent, and are delivered to the addressee. All of this takes just seconds.

## Check on Learning

Select the correct response to the question.

## Check on Learning

Select the correct response to the question.

## Summary

In this topic, you were presented with how information flows on the Internet. Next, you will learn about Information Assurance and we’ll explain some new terms.